Well, Research studies also suggest that getting enough vitamin D may help to prevent high blood pressure, multiple sclerosis and some forms of cancer.

If you're fair skinned, experts say going outside for 10 minutes in the midday sun—in shorts and a tank top with no sunscreen—will give you enough radiation to produce about 10,000 international units of the vitamin. Dark-skinned individuals and the elderly also produce less vitamin D, and many folks don't get enough of the nutrient from dietary sources like fatty fish and fortified milk. Black skin may require six times the sun exposure to make the same vitamin D levels as a very fair-skinned person, but we need more research on this because the studies that have suggested this have been small.

The amount of exposure also depends on the time of the year. In the northern hemisphere, the UVB is more intense during the summer months and less intense during the winter months.

many experts now worry that public-health messages warning about skin cancer have gone overboard in getting people to cover up and seek the shade.

U.S.News got in touch with Robyn Lucas, an epidemiologist at Australian National University who led a study published in the February issue of the International Journal of Epidemiology. Her finding: Far more lives are lost to diseases caused by a lack of sunlight than to those caused by too much.